Highway crossing protection control apparatus



April 30, 1957 E. J. SCHAEFER HIGHWAY CROSSING PROTECTION CONTROLAPPARATUS Filed NOV. 12, 1952 ll! ml.

- IN V EN TOR. Edwin J Scbaefen MAM.

HIS Z47 I HRIVEY' United States Patent HIGHWAY CROSSING PROTECTIONCONTROL APPARATUS Edwin J. Schaefer, Wilmington, N. C., assignor toWestinghouse Air Brake Company, Wilmerding, Pa., a corporation ofPennsylvania Application November 12, 1952, Serial No. 319,875

6 Claims. (Cl. 246-130) My invention relates to highway crossingprotection control apparatus and in particular to a circuit arrangementfor protecting against broken rails in the sections approaching ahighway crossing in non-signaled territory.

It has been common practice to employ directional stick relays inconjunction with track relays to effect the control of highway crossingsignals. These directional stick relays are so controlled that a trainentering a track section at one side of a railway-highway crossingenergizes one of the stick relays which, when energized, establishes astick circuit to maintain itself energized while the train moves throughthe stretch. These directional stick relays also operate when energizedto establish a circuit to supply energy to the highway crossing signalcontrol relay when the track section which includes the intersection isvacated, so that the highway crossing signal ceases to operate when thetrain recedes from the crossing.

Under normal conditions, when the train vacates the section beyond thecrossing, that is the receding section, the stick relay is deenergizedand the crossing signal is thereafter controlled by the track relays sothat the operation of the signal will be initiated on the approach of asecond train moving in the same or opposite direction as the firsttrain.

However, with the arrangement heretofore employed, if a rail in thereceding section should become broken while a train is moving throughthat section away from the crossing, the stick relay will remainenergized. Thereafter, if a train should approach the crossing from theopposite direction .to the first train, no warning of its approach willbe given to highway traffic because, with the stick relay continuouslyenergized, energy will be continuously supplied to the signal controlrelay, and therefore keep the crossing signal deenergized.

It will be obvious that in territory where wayside or cab signalscontrol train movements, a broken rail condition will cause thesesignals to display a restrictive aspect. In such territory, therefore, abroken rail will not create the hazardous condition of a train speedingtoward highway traflic which is not aware of the approach of the train.However, in non-signaled territory, no indication is given of the brokenrail and it is therefore desirable to eliminate the possibility of thehazard existing.

It is an object of my invention to provide improved means of the typedescribed which is so arranged that if a rail in the receding section isbroken during a receding move, the crossing signal will still operatefor a train moving in the opposite direction to the first train.

A further object of my invention is to provide means of the typedescribed which will prevent an energized directional stick relay fromremaining energized if a rail in the receding section should becomebroken during a receding move from a highway crossing.

According to my invention'l. provide two approach sections and acrossing section each provided with a track circuit including a trackrelay. I further provide 2,790,895 Patented Apr. 30, 1957 ice adirectional stick relay, one associated with each approach section. Eachof the approach track circuits includes a back contact of the associatedstick relay. In addition to the ordinary stick circuit for sticking upthe directional stick relay while the train or vehicle occupies thecrossing section, I provide a stick circuit which is closed only if therails of the receding section are shunted by the wheels and axles of areceding train. If one of the rails in the receding section becomesbroken, after the rear wheels of the vehicle pass over the break, thestick circuit will become open and the stick relay will release. Thetrack relay will also be released due to the track circuit being open atthe break in the rail. Accordingly, the signal control relay will bedeenergized and the crossing signal will operate so as to continuouslywarn highway trafiic and indicate to maintainers that something iswrong.

Other objects of my invention will appear hereinafter as thecharacteristic features of construction and mode of operation of myhighway crossing protection control apparatus are described in detail.

I shall describe one form of highway crossing protection controlapparatus embodying my invention, and shall then point out the novelfeatures thereof in claims.

The accompanying drawing is a diagrammatic view of circuit arrangementfor the control of highway crossing signals embodying my invention.

Referring now to the drawing, the reference characters 1 and 2 designatethe rails of a stretch of railway track over which trafiic moves in bothdirections. The track rails are divided by insulated joints 3 into tworelatively long approach sections IT and 2T, and a short track sectionXT which is intersected by a highway H. A crossing signal XS is locatedadjacent the intersection to warn highway traffic of the approach of atrain. The crossing signal XS may be of any appropriate type such as alight signal, or as here shown, an electric bell.

Track sections 1T, 2T and X-T are provided with track circuits includingtrack batteries 1TB, 2TB and XT B, respectively, :and track relays 1T R,ZTR and XTR, respectively.

The crossing signal XS is controlled by a signal control relay XR.Signal control relay XR is, in turn, controlled by the track relays andby two directional stick relays 'WSR and ESR in a manner which will bedescribed presently.

The stick relays ESR and WSR are energized separately by batteries B8Band W313, respectively. The purpose of using these separate batterieswill become clear from the following description. Energy for controlrelay XR and the crossing signal XS may be supplied by any sui-tablesource, for instance, a battery L8.

The apparatus is shown in the condition it normally assumes when thestretch is vacant. At this time the stick relays WSR and ESR aredeenergized. Trackrelay iTR is energized by its associated track battery1TB over back contacts a and 12 of relay WSR and track relay ZTR isenergized by its associated track battery 2TB over back contacts a and bof relay ESR. Signal control relay XR is energized by a circuit whichmay be traced from positive terminal B of battery LB, over front contactb of relay lTR, front contact 0 of relay XTR, front contact I) of relayZTR, and the winding 'of relay XR to the negative terminal N of batteryLB. With relay XR so energized, its back contact a will be open andcrossing signal XS will be deenergized.

I will now assume that an eastbound train approaching from the leftenters the section, thereby causing relay 1TR to release. When relay 1TRreleases, the previously traced circuit for energizing signal controlrelay XR becomes opened at front contact b of relay lTR, and relay XRwill therefore release closing its back contact a. This 3 1 willcomplete an obvious energizing circuit for crossing signal XS which willcommence operating.

When the train enters section X1, the wheels and axles .of thetrain-will shunt relay XTR, thereby causing it to release, thus closingits back contacts 11 and 1b and .opening its front contact .c. This willcause a pick-up circuit for energizing relay ESR to be established. This.ClICLllll may be traced from the positive terminal .of battery ESB,over back contact I) of relay XTR, back contact a of relay IT'R, backcontact .d of relay 'WSR, and the winding of relay ESR to the negativeterminal ofbattcry ESB. Upon the energization of relay ESR, a firststick circuit will be established for maintaining relay ESR picked up.This first stick circuit may be traced from the positive terminal ofbattery ESB, over back contact I; of relay XTR, front contact (I ofrelay ESR, back contact d of relay WSR, and the winding of relay ESR tothe negative terminal of battery ESB. 1T, relay ESR will remainenergized by the first stick circuit.

Upon relay XTR releasing, the previously traced energizing circuit forrelay XR will become open at front contact of relay XTR. Therefore, aslong as the train occupies section XT, relay XR will be released andcrossing signal XS will continue to operate. Furthermore, upon relay ESRpicking up, track relay ZTR will release, since its energizing circuitwill be open at back contacts a and b of relay ESR. Another result ofrelay ESR picking up is that its back contact c will become open andthus insure against relay WSR becoming energized.

When the train enters section 2T, a second stick circuit for maintainingrelay ESR energized will become established. This second stick circuitmay be traced from the positive terminal of battery ESB, over frontcontact a of relay ESR, rail 2 in section 2T, the wheels and axles ofthe train that are occupying section 2T, rail 1 in section 2T, frontcontact b of relay ESR, and the winding of relay ESR to the negativeterminal of battery ESB. When the train vacates section XT, this secondstick circuit will maintain relay ESR picked up.

When the train vacates section XT track relay XTR will pick up and closeits front contract c. This will establish a new energizing circuit forrelay XR which may be traced from the positive terminal B of battery LB,over front contact 1b of relay lTR, front contact c of relay XTR, frontcontact of relay ESR, 'and the winding of relay XR to the negativeterminal N of battery LB. Relay XR will therefore again pick up, thuscausing the circuit which energizes crossing signal XS to become open atback contact a 0f relay XR. Crossing signal XS will accordingly ceaseoperating.

When the train wacates section 2T, the second stick circuit for relayESR will become open since there is no shunt across the rails, and relayESR will therefore release. It should be noted that the polarity ofbattery .ESB opposes the polarity of track battery 2TB and this polarityopposition enables relay ESR to rapidly release and relay ZTR to pick updue to the reestablishment of the original track circuit for section 2T.Upon relay ZTR picking up, the original circuit for energizing relay XRwill be reestablished and relay XR will remain energized. Therefore,crossing signal XS will remain deenergized and not operating. In thismanner, the original condition of the circuit arrangement will berestored.

It should be obvious from the symmetry of the circuit arrangement thatcorresponding circuits would be established or closed andcorrespondingindications would be given highway trafic if .a westboundtrain should proceed through the stretch from right to left.

Let it now be assumed that after an eastbound train has entered section2T, 40118 of the rails in section 2T becomes broken. As long as all thewheels of the train have not passed :over the broken rail, the secondstick circuit for :stick .relay ESR, which was traced from the positiveterminal :of battery ESE, iover front contact a When the train vacatessection I of relay ESR, rail 2, the wheels and axles occupying section2T, rail 1, front contact b of relay ESR, and the winding of relay ESRto the negative terminal of battery ESB, will be closed and relay ESRwill remain picked up. However, when all the wheels have passed over thebroken rail, this stick circuit will become open at the rail break andrelay ESR will release. Upon the release of relay ESR, relay ZTR, whichwas released, will not pick up because its associated track circuit isalso open at the rail break. With both of these relays released. thereis no closed circuit for energizing relay XR, and it too will release.With relay XR released, crossing signal XS will become energized andwill operate continuously. This continuous ringing will give a positiveindication that something is wrong with the circuit arrangement. Andfurthermore, because of the continuous operation of crossing signal XS,highway traffic will be forewarned of any subsequent westbound moves,and, although the warning period may be appreciably longer than theordinary warning period, it will be on the safe side.

From the symmetry of the circuit arrangement, it will be apparent thatif, during the receding move of a westbound train, a rail in section 1Tbecomes broken, signal XS will commence continuous operation and affordample warning to highway trafiic of any subsequent opposing moves.

Although, as I have already pointed out, my invention is particularlyuseful in non-signaled territory, my invention may be used to goodadvantage in territory provided with wayside or cab signals, or both.

Although I have herein shown and described only one form of highwaycrossing protection control apparatus embodying my invention, it isunderstood that various changes and modifications may be made thereinwithin the scope of the appended claims without departing from thespirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track divided into a first, asecond and a third track section by insulated joints, said third sectionbeing between said first and second sections and intersected by ahighway, a first, second and third track relays associated with saidfirst, second and third track sections, respectively, a first and asecond stick relay associated with said first and second track relays,respectively, said first and second track sections each being providedwith a track circuit including its associated track relay and soarranged that the track circuit is open when its associated stick relayis energized, said third section being provided with a track circuitincluding said third track relay, a highway crossing signal adjacentsaid intersection, a signal control relay for controlling said highwaycrossing signal, said signal control relay being controlled by saidthird track relay and jointly by said first track and stick relays andjointly by said second track and stick relays, each of said stick relaysbeing controlled to become energized when the two track relays notassociated with said stick relay are both deenergized, a first stickcircuit, one for each stick relay, closed when said third track relayand the other stick relay are both deenergized, and a second stickcircuit, one for each stick relay, including the rails of the associatedtrack section and adapted to include the wheels and axles of a train insaid associated section.

2. In combination, a stretch of railway track divided into a first, asecond and a third .track section by insulated joints, said thirdsection being between said first and second sections and intersected bya highway and said first, second and third track sections havingassociated therewith a first, a second and a third track relay,respectively; a first and a second stick relay associated with saidfirst and said second track relay, respectively; a first and a secondtrack circuit for energizing said first and second track relays,respectively, each including a back contact of its associated stickrelay; said third track section being provided with a track circuitincluding said third track relay, an energizing circuit means for eachstick relay controlled by a back contact of each of the twonon-associated track relays and a back contact of the other stick relay,a first stick circuit means for each of said stick relays eachcontrolled by a back contact of said third track relay and a frontcontact of said stick relay and a back contact of the other stick relay,a second stick circuit means for each of said stick relays eachcontrolled by a, front contact of the stick relay and adapted to includethe wheels and axles of a train in the section associated with the stickrelay, a highway crossing signal adjacent said intersection, a controlrelay, circuit means controlled by a back contact of said control relayfor energizing said highway crossing signal; and circuit means forenergizing said control relay controlled by a front contact of saidthird track relay and front contacts of said first track and stickrelays in multiple, and front contacts of said second track and stickrelays in multiple.

3. In combination, a stretch of railway track divided into a first, asecond and a third track section by insulated joints, said third sectionbeing between said first and second sections and intersected by ahighway, first, second and third track relays associated with saidfirst, second and third track sections, respectively, a first and asecond stick relay associated with said first and second track relays,respectively, a first and a second track circuit including theassociated track relay and being so arranged that when the associatedstick relay becomes energized the associated track relay is released, athird track circuit including said third track relay, an energizingcircuit means for said first stick relay closed when said second andthird track relays are deenergized and said second stick relay isdeenergized, a first stick circuit means for said first stick relayclosed when said third track relay and said second stick relay are bothdeenergized, a second stick circuit means for said first stick relayadapted to include the wheels and axles of a vehicle in said first tracksection, an energizing circuit means for said second stick relay closedwhen said first and third track relays are deenergized and said firststick relay is deenergized, a first stick circuit means for said secondstick relay closed when said third track relay and said first stickrelay are both deenergized, a second stick circuit means for said secondstick relay adapted to be closed by the presence of wheels and axles ofa vehicle in said second track section, a highway crossing signaladjacent said intersection, a control relay for controlling said highwaycrossing signal, and circuit means for energizing said control relaycontrolled by said third track relay and jointly by said first track andstick relays and jointly by said second track and stick relays.

4. In combination, a stretch of railway track divided into first, secondand third track sections by insulated joints, said third track sectionbeing between said first and second track sections and intersected by ahighway, said first, second and third track sections each havinglassociated therewith first, second and third track relays,respectively, a first and a second stick relay associated with saidfirst and second track relays, respectively, said first and second tracksections each being provided with a track circuit including theassociated track relay and a black contact of the associated stickrelay, said section being provided with a track circuit including saidthird track relay, an energizing circuit means fior said first stickrelay controlled by a back contact of said second track relay and a backcontact of said third track relay and a back contact of said secondstick relay, a first stick circuit means for said first stick relaycontrolled by a back contact of said third track relay and a backcontact of said second stick relay, a second stick circuit means forsaid first stick relay adapted to include the wheels and axles of avehicle in said first track section, an energizing circuit means forsaid second stick relay controlled by a back contact of said first trackrelay and a back contact of said third track relay and a back contact ofsaid first stick relay, a first stick circuit means for said secondstick relay controlled by a back contact of said third track relay and aback contact of said first stick relay, a second stick circuit means forsaid second stick relay adapted to be closed by the presence of wheelsand axles of a vehicle in said second section, a highway crossing signaladjacent said intersection, a control rellay, circuit means forenergizing said highway crossing signal controlled by a back contact ofsaid control relay, circuit means for energizing said control relaycontrolled by a front contact of said third track relay and jointly byfront contacts of said first track and stick relays, and jointly byfront contacts of said second track and stick relays.

5. In combination, a stretch of railway track divided into first, secondand third track sections by insulated joints, said third section beingbetween said first and second section and intersected by a highway, afirst, second and third track relays being associated with said first,second and third track sections, respectively, first and second stickrelays associated with said first and second track relays, respectively,a first track circuit associated with said first section including saidfirst track relay and a back contact of said first stick relay, a secondtrack circuit associated with said second section including said secondtrack relay and a back contact of said second stick relay, a third trackcircuit associated with said third section including said third trackrelay, a first and a second battery, an energizing circuit for supplyingenergy from said first battery to said first stick relay including aback contact of said second track relay and a back contact of said thirdtrack relay and a back contact of said second stick relay, a first stickcircuit for supplying energy from said first battery to said first stickrelay including a back contact of said third track relay and a backcontact of said second stick relay, a second stick circuit for supplyingenergy from said first battery to said first stick relay adapted toinclude the wheels and axles of a vehicle in said first section, anenergizing circuit for supplying energy from said second battery to saidsecond stick relay including a back contact of said first track relayand a back contact of said third track relay and a back contact of saidfirst stick relay, a first stick circuit for supplying energy from saidsecond battery to said second stick relay including a back contact ofsaid third track relay and a back contact of said first stick relay, asecond stick circuit for supplying energy from said second battery tosaid second stick relay adapted to include the wheels and axles of avehicle occupying said second section, a highway crossing signal, acontrol relay, a circuit for energizing said highway crossing signalincluding a back contact of said control relay, a first circuit forenergizing said control relay including a front contact of each of saidfirst, second and third track relays, a second circuit for energizingsaid control relay including a front contact of each of said first stickrelays and said second and third track relays, and a third circuit forenergizing said control relay in cluding a front contact of each of saidfirst and third track relays and said second stick relay.

6. In apparatus for controlling a signal adjacent the intersection of ahighway and a stretch of railway track, said stretch of track beingdivided into first and second approach sections and a crossing section,first and second track relays associated with said first and secondapproach sections, respectively, means responsive to traf fic conditionsin said crossing section, first and second directional stick relaysassociated with said first and second approach sections, respectively, atrack circuit for each approach track section including the associatedtrack relay and controlled by the associated directional stick relay andclosed only when the associated directional stick relay is deenergized,means controlled by said second track relay and said means responsive totraffic conditions in said crossing section and effective only when saidsecond approach section and 'said crossing section are occupied forenergizing said first directional stick relay, a stick circuit for saidfirst directional'stick relay adapted to includethe Wheels and axles ofa train in said first approach section, means controlled by said firsttrack relay and said means responsive to trafiic conditions in saidcrossing section and effective only when said first approach section andsaid crossing section are occupied for energizing said seconddirectional stick relay, and a stick circuit for said second directionalstick relay adapted to include the wheels and axles of a train in saidsecond approach section.

References Cited in the file of this patent UNITED STATES PATENTS1,636,348 Young July 19, 1927 2,080,801 Allen et a1. May 18, 19372,370,704 Allen Mar. 6, 1945 10 2,677,047 Mishclevich Apr. 27, 1954

